Fundamental Theorem Of Calculus

It makes sense when I read the statements but I can't seem to apply it without getting totally lost.

If I have a problem that looks something like:

d/dx of the integral of some function f(x) evaluated from -1 to sin(x) then how do I apply FToC to solve it?

Also what if the bounds are 2x to x^2 or something along those lines?

I also have a related question that I am dead stuck on but an answer to the above would be appreciated more than a solution to the below if you don't have time or something.

2 plus the integral of (f(t)/(t^3))dt evaluated from a to x equals 6x^-5. Find a value for a and a function f(t) so that this is true.